The largest number with meaning?

This is silly, but I sort of wondered.. What is the largest number that has been made, which is somehow related to the world and not just made to be as large as possible?

I was thinking:

Let A be the number of fundamental particles that exist in the universe.
Let B be the volume of the universe divided by the volume of the fundamental particle.
Let C be the the age of the universe divided by the smallest significant time-unit.

A^B^C should be all possible arrangements of all the matter in the universe, at all times?

I cant think of any larger number than that which has some "meaning" to it.

Say we have a cube with sides of 100 centimeters.
Inside that cube, we have 100 smaller solid cubes ("particles") with sides of 1 centimeters.

How many unique ways is there to combine the smaller cubes inside the larger one?

That should be 100^100, no?

Now say that the cube exists for 10 seconds, and we can only operate with units of time as small as 1 second (for the sake of making it simple).

Then there would be 100^100^10 different ways to combine our matter throughout time?

Maybe my math is off, but you get the idea I hope. If you combine all of time with the volume of the universe and the size of the fundamental particle, you get the number of permutations possible for that universe. I want to know if anyone can think of a larger number with practical applications :)

There is a standard answer to this question called Graham's number, which is the largest number ever to be used seriously in a mathematical proof. It is so large that we cannot even come close to writing it down in standard notation.

If you mean the largest number with _physical_ meaning, we can take a cue from the Planck constant, which is on the order of 10^-35. But we have at least four dimensions to deal with, so that becomes 10^-140. There could also be more though. There's also no guarantee that the Planck length is the smallest length, so it could be smaller still.

But once you find that, raise it to the power of the number of dimensions there are, and divide 1 by it, you start to approach the highest orders of magnitude that could possibly have any physical meaning. We're probably in the 10^several hundred, maybe thousands. But probably not more than that.